The American Cancer Society has made a small, but meaningful change in guidelines related to colorectal cancer screening: Adults should now be screened starting at age 45, five years earlier than the previous guideline.

The ACS previously recommended that screening begin at age 50 for those who are at average risk for colon and rectal cancer, and at a younger age for people at higher risk and those with a family history of the disease.

The new guideline, published in CA: A Cancer Journal for Clinicians, states:

The ACS recommends that adults aged 45 years and older with an average risk of colorectal cancer undergo regular screening with either a high‐sensitivity stool‐based test or a structural (visual) examination, depending on patient preference and test availability.

Why did the ACS change the guideline?

One factor prompting the change was a 2017 study published in The Journal of the National Cancer Institute, in which ACS researchers found that compared to adults born around 1950, those born closer to 1990 have double the risk of colon cancer and quadruple the risk of rectal cancer. Additionally, nearly one-third of rectal cancer incidents reviewed in the study were in patients younger than age 55.

Tae Kim, MD, a colorectal surgeon at Intermountain Healthcare’s LDS Hospital, thinks the change is important news. He says that while other cancer screenings like mammograms only help to catch early cancer, a screening colonoscopy can find polyps that could eventually turn into cancer. Twenty percent of patients over 50 will have polyps, and if we remove them, we can stop the cancer before it begins.

“We’ve known about the effectiveness of preventive screenings at a younger age for some time,” said Dr. Kim. “It’s good to change the screening guidelines to reflect these concerns. With this new recommendation, hopefully we can prevent more cases of colon and rectal cancer.”

The data included in the ACS study falls short of predicting what might be causing the increasing colorectal cancer trend, and instead calls for more research to help discover the cause.

What type of colorectal screening is recommended?

As part of the new guidelines, the ACS identifies six options for screening tests; three high‐sensitivity stool‐based tests and three structural examinations. Studies suggest that both stool‐based colorectal cancer screenings and structural examinations, such as a colonoscopy, perform similarly in detecting cancer among individuals younger than 50 years and among older individuals. However, the ACS says all positive results from non-colonoscopy screenings should be followed up with a timely colonoscopy.

What is a high‐sensitivity stool‐based test?

These are noninvasive laboratory tests that include:

• Fecal immunochemical test (administered annually)
• High‐sensitivity, guaiac‐based fecal occult blood test (administered annually)
• Multi-target stool DNA test (administered every three years)

What is a structural (visual) examination?

This is the type of screening most people tend to think of when they refer to colorectal screening, which includes:

• Colonoscopy (administered every 10 years)
• CT colonography (administered every five years)
• Flexible sigmoidoscopy (administered every five years)

As with any medical screening, people are encouraged to review their individual health insurance policy to determine which options are covered before they choose to get screened.